Crumbing mechanism for excavating machines



Feb. 27, 1962 H. MEYER ETAL 3,022,584

CRUMBING MECHANISM FOR EXCAVATING MACHINES INVENTORS F a 5 HENRY L. MEYER,

FRED 'R. WILHELM m BY Elmuun Gnecoaczix an, mm 11% k5,,

HTTORNEYS Feb. 27, 1962 MEYER ETAL 3,022,584

CRUMBING MECHANISM FOR EXCAVATING MACHINES E5 INVENTORS HENRY L. MEYER, I. FRED WI'LHELM H" r l: a a

BY EDMUND Gazsoaczix Tell! I Kilauea, Y 5:11

RTTOR NEYS Feb. 27, 1962 3,022,584

H. L. MEYER ETAL CRUMBING MECHANISM FOR EXCAVATING MACHINES Filed Sept. 16, 1959 5 Sheets-Sheet 4 INVENTORS HENRY L. MEYER,

FRED R. WiLHELM m Emunn Gazeonczix Feb. 27, 1962 H. L. MEYER ETAL 3,022,584

CRUMBING MECHANISM FOR EXCAVATING MACHINES Filed Sept. 16, 1959 5 Sheets-Sheet 5 0] (9 @1 I o 9 I 1 i -INVENTO/RS HENRY L. MEYER, FRED R. WiLHELM -Q BY EDMUND GREGORCZK T na Mum, zmaaesl F130;

HTTwarm s United States Patent 0 3,022,584 CRUMBING MECHANISM FGR EXCAVATENG MACHINES Henry L. Meyer, Cleveland Heights, and Fred R Wilhelm and Edmund Gregorczik, Willowiclt, Ohio, assignors to The Cleveland Trencher Company, Cleveland, Ohio, a corporation of Ghio Filed Sept. 16, 1959, Ser. No. 840,331 16 Claims. (Cl. 3780) This invention relates in general to improvements in trench excavating or ditching machines, and more particularly to a trench excavating machine having an 1mproved crumbing mechanism which may be selectively and expeditiously moved to and from active position.

Crumbing mechanisms for excavating machines are known in the art and include a crumbing shoe attached to the outer end of the boom of the excavating machine. This shoe extends downwardly from the boom to the floor of the trench or excavation, and is so shaped as to shove or propel loose material on the floor of the trench forwardly so that it may be picked up by the excavating buckets of the machine and removed from the trench, thereby maintaining the floor of the trench comparatively clean. Such crumbing mechanism also helps in maintaining a constant grade trench bottom by-stabilizing the digging unit at its depth ofroperation. It is also known in the art to swingably mount such crumbing shoe to the outer end of the boom for pivotal movement in a generally vertical plane, so that the crumbing shoe can be selectively moved. into and'out of active position, thus providing for raising the shoe clear of the trench and thereby increasing the positioning and maneuverability characteristics of the machine. When it is necessary or desirable to have the digging wheel of the excavating machine dig straight downwardly, the crumbing shoe must be swung upwardly and rearwardly to etfect its clearance above the unexcavated ground. When the digging wheel has reached full depth and has proceeded forwardly at sufficient distance to provide room in the trench for the crumbing shoe, the digging wheel is generally raised and then the crumbing shoe is lowered and manually locked in position, after which the digging proceeds.

Various mechanisms have been utilized in the past for so pivoting and maintaining the crumbing shoe in and out of operating position, with all such mechanisms generally necessitating a considerable amount of manual operations to effect the proper positioning of the crumbing shoe. Some such mechanisms that have been used are cables and cranks, geared winding drums for power activation t the crumbing mechanism, and/ or levers or the like for manual operation. None of the latter arrangements have been found to be completely satisfactory and have been found either to be undependable in operation, bulky and unduly space consuming in nature and/or awkward and time consuming in the accomplishment of the desired function. a

In the pending application of John W, Spring Serial No. 755,010, filed August 14, 1958, now Patent No. 2,908,091, there is disclosed a novel crumbing mechanism for excavating machines which is actuated by means of a fluid powered motor, thereby providing for the rapid and selective positioning of the crumbing shoe by the operator of the machine, and which is expeditiously controlled from the operators work area on the machine, thus greatly reducing the labor and time involved in such operations.

The present invention provides a fluid powered crumb ing mechanism which embodies certain improvements over the aforementioned Spring arrangement, as for instance by eliminating all eccentric loading on the boom of the trenching machine, whereby all stresses are gen- 3,$ZZ,554 Patented Feb. 27, 1952 erally equally applied to the boom, and therefore eliminating the need for additional bracing. In addition, the present invention provides an automatic locking device for holding the crumbing shoe in normal operating position, and upon actuation of the crumbing shoe toward inactive or inoperative position, the locking mechanism is automatically deactivated. The present invention in one embodiment thereof also provides a multiple part crumbing shoe which may be readily extended in length and/or adjusted positionally with respect to the digging unit, thereby providing a crumbing shoe kit which is adapted for use on various sizes and models of excavating machines, thus making the mechanism more economically desirable and greatly increasing its useability,

Accordingly an object of the invention is to provide an excavating machine embodying an improved crumbing mechanism.

Another object of the invention is to provide an excavating machine embodying improved crumbing mechanism actuated by a fluid powered motor unit for rapidly and selectively positioning the crumbing shoe into and out of active position, and including a locking device which is operative to automatically lock the crumbing shoe in operative position and to automatically deactivate itself upon actuation of the mechanism for movement of the crumbing shoe toward inactive position.

A further object of the invention is to provide an excavating machine including generally horizontally extending boom structure and embodying improved crumbing mechanism of the latter type, and wherein the crumbing mechanism may be positionally adjusted so as tooperatively extend downwardly at various distances with respect to the boom structure and the associated excavating unit, and including means for adjusting the position of the locking device of the crumbing mechanism with respect to the crumbing shoe.

A still further object of the invention is to porvide a crumbing mechanism of the latter type wherein the crumbing shoe is of a multiple part construction, providing for selective elongation of the shoe and/or positioning of the shoe proper closer to or farther from the associated excavating unit, thereby providing for the use of the mechanism with a range of sizes of excavating units and greatly increasing the useabiilty of the device.

Another object of the invention is to provide an improved crumbing mechanism which is comparatively uncomplicated in nature and which may be readily added to existing excavating machines or may be easily embodied in new machines, and which is adapted to be readily swingable into and out of active position, and which Incorporates means for automatically locking the crumbing mechanism in operative position and for automatically deactivating the locking means upon actuation of the crumbing mechanism toward inoperative position.

Other features and advantages of the invention will be apparent from a consideration of the following description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is a side elevation of an excavating machine embodying the instant invention.

FIG. 2 is a fragmentary, enlarged, side elevational view of the outer end of the boom and associated crumbing mechanism of FIG. 1, and illustrates in greater detail the arrangement of the instant invention including the locking means for automatically locking the crumbing shoe in operative position. In dot-dash lines, the fully locked position of the mechanism is illustrated, and in full lines the position of the mechanism during initial actuation to move the crumbing shoe toward inactive position is shown.

FIG. 3 is a fragmentary, enlarged, top plan view of the structure illustrated in FIG. 2.

3 FIG. 4 is a fragmentary, enlarged, end elevational view taken generally from the right hand side of FIG. 2. FIG. 5 is an enlarged, top plan view of the latching I or' locking device per se, utilized, in the FIGSJI to 4 assembly;

FIG. 6 is an enlarged, fragmentary, side elevational view of a crumbing mechanism embodying the aforementioned automatic locking device, and illustrating a modified multi-part crumbing shoe for use in selectively ad- "justing the crumbing shoe proper longitudinally with respect to the excavating unit, thereby permitting the use of the mechanism with various sizes of excavating units and/or under var ous operating conditions.

FIG. 7 is an end elevational view taken from the right hand side of FIG. 6.

FIG. 8 is an' enlarged, fragmentary, side elevational view of a crumbing mechanism generally similar to FIG.

6,'but illustrating a further modification includ ng side plate extensions for the shoe proper, for also providing for extension of the crumbing shoe proper.

FIG. 9 'is an end'elevational viewtaken from the right l hand side of 1 16.8.

, Referring again to the drawings, and espec'ally to FIG. 1 thereof, there is shown a trenching machine of the well known wheel type, embodying the instant invention. Such an excavating or trenching machine broadly comprises a main frame 10, supported on suitable tractor treads 12,

j a main power plant or internal combust'on engine 14 supported on the forward end of frame 10, mast structure 16 for supporting a vertically movable boom structure 18, an excavating wheel or unit 20 rotatably mount- 'ed on boom 18 by means of frame and wheel arrangement 22 and 22a and drivingly connected to the motor nnit 14 of the machine by the chain and sprocket arrangement generally referred to by reference number 24, 1 and a transversely extending discharge conveyor 26'which is adapted to receive material from digg'ng unit 20 and carry it to either side of the machine.

Boom structure 18 is pivotally mounted as at'28 'for movement in a generally vertical plane, and may be raised and lowered on mast'structure 16 by means of cable and pulley systems 30 actuated by winding drums 32 and 34 mounted Y on the machine chassis and in a manner well known in the art. It will be understood of course, that other structural arrangements and systems could be utilized for controlling the movement of boom 18 and associated digging unit 20 without departing from the scope of'the invention.

The controls for operating the various components of ,the machine, including the aforementioned main power plant 14, the winding drums 32 and 34, the digging unit 20,'etc. may include the levers 36, 37, 38, and 39, as

shown, with the latter being localized in a particular area on the machine for convenient access by the machine operator and from one general location.

The crumbing mechanism of the instant invention is v generally indicated by reference number 40, and as shown, comprises an elongated generally arcuate shaped in side elevation box-like structure 42, known as a crumbing shoe, and pivotally mounted as by means of removable bolt or, shaft element 44 to the outer end of boom 18.

A rotation multiplying, articulated linkage 46 is pivotally connected to the boom as at 48, and to the crumbfng shoe,

2 as at 50, for swinging the crumbing shoe about its pivotal connection 44to the boom and thus move the crumbing shoe into and'out of operative position. A reciprocal type, double-acting, finid powered motor unit 52 is pivot- .ally connected at one end, as at 54, to the articulated f jo'nt of the linkage structure 46, and at the other end separable fastener element therethrough, and thus adjustably maintain portion 58 in predetermined position.

The upper end of shoe 42 includes spaced and generally upwardly tapered side plate portions 64 which, as aforementioned, provide for the pivotal mounting of the shoe as at 44 to the outer end of the boom. Side plate portions 64 are received intermediate transversely spaced supporting plate elements 68 which are secured to the outer end of the boom, and which include a plurality of transversely aligned vertically spaced openings 70 therein for changing the pivot point of the crumbing shoe with respect to the boom. It will be seen that the axis of rotation of the crumbing shoe may be readily changed by mounting the pivot pin or shaft 44 in any selected transversely al gned pair of the vertically spaced openings 70 in supporting plate elements 68. The bottom edge 74 of each of the plates 68 is tapered downwardly in a forward direction, and the inner ends of plates 68 are provided with a plurality of vertically spaced and transversely aligned openings 76 therein as shown. Opposing pairs of openings 76 in plates 68 are adapted for rece ving a transverse anchor shank or bolt 78 (FIG. 2) therein, for a purpose to be hereinafter described.

The articulated rotation multiplying i linkage 46 comprises a pair of transversely spaced, generally inverted V-shaped crank "elements 80, connected .by crossmemhers 80a, and rotatably connected as aforementioned at e 48 as by means of a transverse shaft element, to the outer end of the boom, and at their other ends are rotatably connected as by means of aforementioned detach able shaft or bolt element 54 to transversely spaced lifter lnk elements 86. Lifter link elements 86 are connected by cross member 86a and are in turn journaled at their inner ends, and as by means of transverse pin 50, to the upper side plate portions 64 of thecrumbing shoe.

The fluid powered motor unit 52 has the outer end of its cylinder'element pivotally connected to the pivotal joint 54 of the rotation multiplying linkage 46 wh Ie the end of the piston rod element of the motor unit is pivotally mounted as at 56 on the transverse pivotal joint 44 of the crumbing shoe to the boom. It will be seen that the linkage 46 and actuating motor unit 52 are centrallyarranged at the outer end of the boom, thereby eliminat'ng all transverse eccentric loading on the boom,

to insure equal application of stresses thereto.

The pivotal connection of each of the lifter link elements 86 tothe respective upper side plate portion 64 of the crumbing shoe includes'an elongated slot 90 (FIG. 2) in each of the side plates in which aforementioned pin element is adapted to move lengthwise of the -'slots, as will be hereinafter'described in greater detail. In the embodiment of the invention illustrated, washers 92 and cotter pin elements 92a (FIG. 4) prevent pin 58 from inadvertent movement out of journaled position in slots 90.

In accordance with the invention, an automatic locking mechanism is provi-led comprising a latch member 94 (FIG. 5) pivotally mounted on transverse shaft 95 f (FIGS. 2 and 4) which in turn has its terminal ends supported in elongated slots 96 in each of the upper side plate port'ons 64 of the crumbing shoe. The latch mem- 'ber comprises a pair of transversely spaced arm elements 98 (FIG. 5) rigidly interconnected by girder or rib element 98a.

The inner end of'each of arm elements 98 comprises an upwardly facing U shaped,.in side elevation, slot or recess 99 which is adapted to receive the aforementioned transversely extending anchor bolt element 78 extend'ng through openings 76 in the supporting plate elements 68, in the locked position of the latching device, to positively lock the crumbing shoe in operative position. The other 'or outer'end, of each of arm -elements 98 comprises an elongated generally lengthwise extending opening'100 therein. Open'ngs 1G0 receive therethrough transverse pin 50 which pivotally connects linkage 46 to the crumbing shoe. Each arm 98 also has an opening 101 therethrough for receiving shaft 95 to pivotally mount the latch on the crumbing shoe.

Shaft 95 has a threaded bolt element 1 .32 extending through each of its terminal ends, generally transverse to the axis of the shaft, and disposed outwardly of upper side plate portions 64 of the crumbing shoe. The shank portion of each of bolt elements 102 passes through an opening in a bracket 184 secured to the respective side plate portion 64 and extending laterally therefrom. Threaded nut element 1G5 (PEG. 2) maintains the associated bolt 102 in secured relation with shaft 95, and threaded nut elements 1: 37 provided for adjustment of the axis of rotation of the latching device 94 longitudinally with respect to the side plate portions 64. It will be seen that movement of nut elements 137 along bolt 1(52 will move the shaft 95 in the associated elongated slot 96, and thus adjust the position of the pivotal axis of the latching device 94. The purpose of the latter is to provide an arrangement for readily adjusting the position of the latch memher, and especially the position of the recesses 99 in the inner end thereof with respect to the anchor shaft or bolt element 78, if the axis of rotation of the crumbing shoe is lowered with respect to the boom and from the position illustrated in FIG. 2 of the drawings. By moving pin 44 to a lower set of the transversely spaced openings 70 in supporting plate portions 64, the pivotal axis of the crumbing shoe will be lowered, and the outer ends of lifter links 85 of articulated linkage 46 are provided with a plurality of openings 168 for correspondingly adjusting the pivotal connection of levers 8i and links 86. Since the latching mechanism 94 is moved downwardly with the crumbing shoe upon downward movement of the axis of rotation of the latter, each of supporting plate portions 68 is provided with a separate extensible section 109 which may be extended downwardly and be secured in such extended position as by means of fasteners 110, such extended sections mounting the anchor shaft 78 at their lower ends. Thus the anchor shaft 78 may be lowered to a position corresponding to the changed position of the axis of rotation of the crumbing shoe, for locking coaction with the latching arms 93, and the axis of rotation of the latch arms may be adjusted by means of the aforediscussed adjusting bolt arrangement 162, to insure proper coaction between the recesses 99 in the inner ends of the latching arms and the anchor shaft 78.

Operation of the mechanism will now be described. As may be best seen from FIG. 2, latching arms 98 of latching device 94 are in substantially horizontal position when the crumbing shoe is in normal operating and locked condition, as shown in dot-dash lines. Upon supplying motor unit 52 with pressured fluid as by means of feed line 112, which is connected to a suitable source of fluid, the piston rod 111 of motor unit 52 commences its outward stroke with respect to its associated cylinder. This outward movement of the piston rod initially merely lifts pin 50 to the upper end of each of slots 90 in the upper side plate portions 64 of the crumbing shoe, and toward the outer end of each of openings 100 in arms 98 of the latch 94 and substantially to the position illustrated in full lines in FIG. 2 of the drawings, and thus pivots the latch member 94 about its pivotal connection 95 to the crumbing shoe, to automatically unlock the latching arms 98 of the latch from holding coaction with anchor shaft 78. It will be seen therefore that the initial outward movement of the piston rod of the motor unit merely unlocks the latching mechanism, and is not adapted to cause any upward pivotal movement of the crumbing shoe. Upon further outward movement of the piston rod with respect to its associated cylinder, the rocker arms 80 of the lifter linkage are caused to rotate further in a counterclockwise direction, as viewed in FIG. 2, about their pivotal connection 48 to the boom, and the crumbing shoe is caused to pivot upwardly due to the pull on drag links 86. It will be seen from FIG. 2 that the pivotal connection 54 of the rocker arms 86 to the lifter links 86 is disposed above a plane perpendicular to the plane of the paper of FIG. 2 and passing through the pivotal axis 48 of the rocker arms 89 to the boom and the pivotal axis 44 of the motor unit 52 to the boom, to ensure the upward pivotal movement of the shoe from the operative position illustrated to an inoperative upwardly swung position wherein the crumbing shoe is disposed generally above the boom. In the latter inoperative position, the crumbing mechanism is disposed out of interferring relation with respect to the end of the boom and associated excavating unit 29 to facilitate the maneuverability of the trenching machine. Upon supplying working fluid via feed line 114 to the opposite end of the cylinder of motor unit 52, the piston rod is retracted and the crumbing shoe is quickly caused to pivot downwardly toward its operative position. During lowering of the crumbing shoe, the weight ofthe shoe causes the pine 50 to be maintained in the upper ends of slots 90 in side plates 64 and thus maintains the latch in its inactive or open position until abutment surfaces 116 on the latch arms 93 engage the anchor shaft 78, and

. then additional clockwise movement, as viewed in FIG. 2,

of the cylinder and associated downward movement of links 86 forces pin 50 toward the bottom ends of slots 90 in side plates 64 and thus pivots the latch into locking coaction with the anchor bar 78' to automatically lock the crumbing shoe in operative position. In the operative locked position of the crumbing shoe, the latch 94 is held in engagement by the hydraulic pressure in the motor unit- 52 and by the combined weight of the motor unit 52 and associated linkage 46, thereby obviating any possibility of unlatching by accidental slipping, and yet Without my material application of stress to the motor unit.

The motor unit 52 and associated feed lines 112, 114 may be connected to a conventional hand-operated control valve, as for instance diagrammatically illustrated valve mechanism 118 (FIG. 1) and to a source of supply of working fluid, as for instance a pump and fiuid reservoir mounted on the excavating machine frame and operatively connected to the main power unit 14 of the machine in a manner well known to those skilled in the art. The operating valve 118 for the hydraulic system controlling motor unit 52 is preferably located in the machine operators work area in the vicinity of the aforementioned control levers 36, 37, 38, 39, and as shown, thereby permitting the machine operator to control the movement of the crumbing shoe in an expeditious manner.

Referring now to FIGS. 6 and 7, there is shown a modified form of crumbing shoe proper embodying the afoirediscussed fluid powered actuating mechanism and latching mechanism, for controlling the crumbing shoe. In this embodiment, the drag links 86 of the articulated shoe actuating linkage 46 are of a slig tly different construction as compared to drag links 86 of the first described embodiment in that the lower ends of links 86' are bifurcated as at 129 and connected by cross pece 122 and then individually pinned or iournaled, as by means of laterally spaced pins 5G, to the respective side plate support portion 64 of the crumbing shoe. Cross pieces 122 are adapted for engagement with edge surface 124 of the respective side plate portion 64 to limit upward rotation of the shoe in the upwardly swung inoperative position thereof.

Side plate portions 64 are detachably connected to the working section 42 of the shoe proper, with the latter being provided with ear portions 126 for pivotally mounting the shoe, as at 128, to the side plate portions 6 The shoe working section 42 has a plurality of rearwardly extending threaded studs 130 secured to its rear face, such studs extending through a bracket 13?. extending transversely between the bottom ends of side plate portions 64 and secured thereto by fastener assemblies 134. Threaded nuts 136 coacting on opposite sides of transverse wall 138 of bracket 132 and with the respective threaded stud 130, adjustably maintain the shoe section 42' in non-pivotal relation with side plate portions 64'. a

Side plate portions 64' are provided with' a plurality of longitudinally spaced openings 140 therein for adjust-:

ing the pivotal axis 128 of the crumbing shoe section 42' closer or further away from the digging wheel or unit 20, to thereby provide for the use of the crumbing mechanism with different sizes of digging wheel and under dill- 'ings 70 in adapter plates 142 secured to boom side plate extensions 63, provide for vertically adjusting the erent operating conditions, and vertically spaced openpivotal axis of the crumbing shoe side plate portions 64 Y to the boom, the same as in the first described embodiment. As can be seen in FIG. 6, the aforementioned ex;

tension plates 109 supporting anchor shaft 78 are shown in lowered position.

The aforementioned fastener assemblies 134 are preferably of the shear type so that if the crumbing shoe 7 section 42' engages an obstruction, the fasteners134- will shear off after application of predetermined stress, and

the shoe section 42' may then freely pivot about its a pivotal axis 128 to the side plate portions 64', to prevent damage to the crumbing mechanism.

Referring now to FIGS. 8 and 9, there is shown a;; further modification of the crumbing shoe proper, such further modification being generally similar to the FIGS. 6 and 7 embodiment except that the shoe has been positioned downwardly or in effect extended, by means of cured to side plate portions 64'.

elongated extension plate members 144 detachably se- The shoe section 42 is pivoted as at 128' to the side plate portions 64 and 7 associated extension plates 144, and is maintained in predetermined position by rearwardly extending stud elements 130 coacting with nuts 136 and bracket 132,1,

the latter being mounted on the lower ends of extension plate members 144 and secured thereto as by the shear type fastener assemblies 134. The extension plates 144 have longitudinally spaced openings 148 therein which are adapted for alignment with the corresponding open ings 140 in the side plate portions 64 for moving the pivot axis 128' of the shoe section 42' longitudinally of the boom and thus moving it closer or further away from the digging unit.

the excavating unit in a longitudinal direction, and wherein the locking mechanism is adjustable so that it may be coordinated with the'adjustability of thecrumbing shoe proper, to insure proper coaction between the i operating parts of the locking mechanism in the operative position of the crumbing shoe.

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of any of' the features described or shown, or portions thereof, but that it is recognized that various modifications are possible within the scope of the invention claimed.

We claim: 1. In an excavating machine having a generally horizontally extending boom, an excavating unit; mounted on 7 said boom, crumbingmechanism including a crumbing shoe pivotally mounted on said boom adjacent said unit, a fluid powered motor unit operatively connected to said boom and to said crumbing shoe for pivoting the latter into and out of operative position and in a generally vertical plane about its pivotal connection to'said boom, and automatic locking meansincluding means movable with respect to said shoe and other meansadapted for locking coaction with said movable means, for main taining said crumbing shoe in said operative position.

2. In an excavating machine having a rearwardly extending elongated boom, an excavating unit mounted on said boom, crumbing mechanism including a crumbing shoe pivotally mounted on said boom adjacent said excavating unit for swinging movement in a generally ver- 'tical plane into and outof operative position, a double acting fluid powered motor unit mounted on said boom, linkage means mounted on said boom and being operatively connected to said motor unit and to said crumbing shoe, said motor unit and said linkage means being symmetrically'aligned with respect to the longitudinal vertical center plane of said boom, means forvactuating said motor unit, and automatic locking means operative upon actuation of said motor unit, for locking said crumb- A spacer member 150 is also provided in this embodi-r ment, which is pivoted to the side plate portions 64' and extension plates 144, as at 152, and which is disposed intermediate the top wall 154 of the crumbing shoe and a transverse web 156 secured to the side plate portions 64', for further rigidifying the connection of the shoe section 42 to the side plate portions 64'. Spacer mem- .ber 150 may be positioned longitudinally of the boom together with the crumbing shoe section 42, and the aforementioned web 156 diverges upwardly, as at 156a,

to provide for such forward positioning of the spacer 150 without interference with the web 156.

From the foregoing discussion and the accompanying drawings it will be seen that the invention provides an improved power actuated crumbing mechanism which may-be rapidly and selectively swung to and from oper--- ative position and wherein the actuating means for the crumbing mechanism is so supported and disposed on the boom of the associated excavating machine that the stresses placed upon the boom by the power actuation of the crumbing shoe are equalized. The invention also,"

provides an automatic locking mechanism for the crumbing shoe which automatically locks the crumbing shoe in normal operating position and which is automatically unlocked upon actuation of the power mechanism to pivot the shoe to inoperative position. In addition, the invention provides a crumbing mechanism of the latter mentioned type which is adjustable and which is adjustably mounted on the boom of the excavating machine so that it may extend downwardly at various distances ing shoe in operative position, said locking means including means pivotable with respect to said shoe and other means mounted on said boom, said pivotable means being movable into locking coaction with said other means upon predetermined actuation of said motor unit.

3. In' a crumbing mechanism for excavating machines and the like, a generally horizontally extending support,

a crumbing shoe pivotally mounted on said support in depending relation therefrom when in normal operating position and adapted tovbe pivoted upwardly to an inoperative position, a fluid powered motor unit attached to said support, lifter linkage means mounted on said support and operativelyconnected to said motor unit and to said'shoe, said motor unit coacting with said linkage means to rotate said shoe about its pivotal connection to said support to move said shoe to inactive position,

and automatic latching means on said shoe and on said support for locking said shoe in normal operating position upon actuation of saidmotor unit and movement I of said shoe to said last mentioned position, said latching means including an arm pivotable with respect to said a shoe and an abutment mounted on said support, said arm with respect to such boom structure and the associated:

' excavating unit and/or be disposed further or closer to mounted on said support and operatively connected to said motor unit and to said shoe for pivoting the latter in a generally vertical plane from an operative position wherein said shoe is disposed in generally depending relation with respect to said support to an inoperative position wherein said shoe is disposed generally above said support, said linkage means including a rocker arm pivotally mounted adjacent one end of said support and extending outwardly therefrom and a drag link pivotally connected adjacent one end to the outer end of said rocker arm and pivotally connected at its other end to said shoe, said motor unit at its other end being operatively connected to said linkage means, and automatic locking means operable to maintain said crumbing shoe in said operative position, said automatic locking means including an element movable with respect to said shoe and mounted thereon and anchor means on said support adapted for holding coaction with said movable means upon movement of said shoe to said operative position, to lock said shoe in said last-mentioned position.

6. In a crumbing mechanism in accordance with claim wherein said movable means comprises a latching'arm pivotally mounted on said shoe for movement in a generally vertical plane, means coupling said latching arm to said link, said latching arm having an upwardly facing recess therein, and said anchor means comprising a transversely extending shaft mounted on said support and adapted to be received in holding relation in said recess.

7. In a crumbing mechanism in accordance with claim 6 wherein the pivotal connection of said link to said shoe comprises a transversely extending element mounted on said link and movably disposed in an elongated generally lengthwise extending slot in said shoe, said latching arm being pivotally connected to said drag link, whereby said latching arm is automatically pivoted out of locking position with said anchor means on said support structure upon actuation of said motor unit to move said shoe to inoperative position.

8. A locking mechanism for a crumbing shoe of an excavating machine and the like wherein the 'crumbing shoe is pivotally mounted on a generally horizontally extending support structure for movement from an operative position wherein the shoe is in depending relation to the support structure to an inoperative position where in the shoe is swung vertically upwardly from said operative position, said locking mechanism comprising an arm pivotally mounted on said crumbing shoe for movement in a generally vertical plane, said arm having an open slot in a marginal edge portion thereof, abutment means mounted on said support structure, said abutment means being adapted to be received in said slot upon pivoting of said arm when said shoe is in said operative position to lock said crumbing shoe in said last mentioned position.

9. In a locking mechanism in accordance with claim 8 including a fluid powered motor unit for pivoting said shoe into and out of operative position and means operatively connecting said motor unit to said locking mechanism for automatically moving said arm into and out of locking position upon actuation of said motor unit.

10. In a crumbing mechanism for excavating machines and the like, a generally horizontally extending elongated support, a crumbing shoe pivotally mounted on said support in depending relation therefrom when in normal operating position and adapted to be pivoted upwardly to an inoperative position, a fluid powered motor unit operatively connected to said support and to said shoe for pivoting the latter into and out of operative position, automatic locking means for maintaining said shoe in said operative position including means for automatically deactivating said locking means upon actuation of said motor unit to move said shoe out of operative position, and means for adjusting the position of said shoe and said locking means in a vertical direction with respect to said support.

11. In a crumbing mechanism in accordance with claim 10 wherein said shoe comprises an upper support section pivotally connected to said support and a lower working section detachably secured to said upper support section, and means on said last mentioned section for selectively adjusting the position of said working section in a direction lengthwise of said support.

12. In a crumbing mechanism in accordance with claim 11 wherein the connection of said lower working section of said shoe to said upper support section thereof includes shear means adapted to fracture upon application of predetermined stress to said working section to prevent distortion and damage to said crumbing mechanism.

13. in a crumbing mechanism in accordance with claim 11 including means for selectively lowering the connection of said working section of said shoe to said support section thereof to thereby elongate said shoe with respect to its pivotal connection to said support.

14. In a crumbing shoe device adapted for mounting on the excavating unit carrying boom of a trenching machine comprising an upper support section adapted for connection to the boom and a lower working section detachably secured to said upper support section, and means on said upper section for selectively adjusting the secured position of said working section to said upper section in a direction lengthwise of the boom.

15. In a crumbing shoe device in accordance with claim 14 wherein said working section is pivotally attached to said upper support section and including shear means coacting between said upper section and said working section to normally prevent pivotal movement of said worknig section with respect to said upper section unless said working section is subjected to a predetermined stress limit at which time said shear means is adapted to fracture to permit such pivotal movement to thereby prevent distortion and damage to said crumbing shoe device.

16. In a crumbing shoe device in accordance with claim 14 including means attached to said upper section and to said working section for selectively lowering the connection of the working section to the support section to thereby elongate said crumbing shoe device.

References Cited in the file of this patent UNITED STATES PATENTS 2,647,789 Chayne Aug. 4, 1953 2,649,792 Miller Aug. 25, 1953 2,654,966 Askue Oct. 13, 1953 2,776,853 Billstrom Jan. 8, 1957 2,908,091 Spring Oct. 13, 1959 

